A method which includes dispersing a resin (b) or a precursor (b0) of the resin (b) in an aqueous dispersion of resin particles (A), followed, if using the precursor (b0), by causing the precursor (b0) to react, to form resin particles (B) comprising the resin (b) in an aqueous dispersion of the resin particles (A), thereby forming an aqueous dispersion (X1) of resin particles (C) having a structure where the resin particles (A) are adhered on the surface of the resin particles (B), and the resin particles (B) and the resin particles (C) obtained by removing an aqueous medium from the aqueous dispersion (X1) are known (Patent document 1).
Patent document 1: WO 01/60893